Server Offline as soon as trying to access Octoprint from a browser

What is the problem?

I have been successfully using octoprint for many months now. Recently I have started to get server is offline error as soon as I try to access Octoprint from a browser.

What did you already try to solve it?
I have tried rebooting Pi
I looked at the forum for similar cases. I couldn't find a feasible solution.

Additional information about your setup (OctoPrint version, OctoPi version, printer, firmware, octoprint.log, serial.log or output on terminal tab, ...)
Octoprint Version: 1.3.8
OctoPi Version: 0.14.0
Printer: Prusa i3 mk2s
Firmware: Marlin

I can sucessfully SSH into the Pi using my computer.

octoprint.log (14.5 KB)


  • Your workstation is at a college
  • The printer is at that college
  • Your I.T. staff have made changes to their internal firewalls
  • Those IP addresses in your log ARE PUBLIC IP ADDRESSES!!!!1!1111

I can only hope you've setup access control on that.

Your first two assumptions are right. The printer is in a lab in a university.
It is possible that recent changes to firewall are made by IT staff

Though the IP addresses look public, they are not visible to outside world. They can be only accessed through a special VPN.

Ofcourse, the access control is turned ON with https authentication.

So, do you think the problem is with the changes in firewall rules? Can it be narrowed down?

Run Octoprint with your plugins disabled. See if that helps.

Plugins might not be the issue here. But I can try.

How can I run octoprint with plugins disabled? The server immediately disconnects when I try to access Octoprint server from a browser.

Presumably, some sort of ~/.octoprint/config.yaml editing might do that without the web interface.

As a long-time I.T. Manager, I would imagine that someone could have edited the internal firewalls at the college. It sort of looks like you and the printer are on the same subnet of your CLASS C or whatever you have there. Even so, I know places where there is limited peer-to-peer connectivity on the wi-fi network due to security concerns.

You might try both the http: and https: versions of your printer's interface.

1 Like

See How to start OctoPrint in safe mode - there are several ways.

I finally traced the issue back to internal IT firewall. It is now resolved.

It's always the I.T. staff... :man_facepalming:

1 Like